[PATCH 4.9 025/148] btrfs: fix missing error return in btrfs_drop_snapshot

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jeff Mahoney <jeffm@xxxxxxxx>

commit e19182c0fff451e3744c1107d98f072e7ca377a0 upstream.

If btrfs_del_root fails in btrfs_drop_snapshot, we'll pick up the
error but then return 0 anyway due to mixing err and ret.

Fixes: 79787eaab4612 ("btrfs: replace many BUG_ONs with proper error handling")
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/btrfs/extent-tree.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9362,6 +9362,7 @@ int btrfs_drop_snapshot(struct btrfs_roo
 	ret = btrfs_del_root(trans, tree_root, &root->root_key);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
+		err = ret;
 		goto out_end_trans;
 	}